Re: Linux should better cope with power failure

[David Balazic <david.balazic@uni-mb.si>]

Gerhard Mack wrote:
> 
> This sounds very nice.. can such a thing be done with the reset switch as
> well?

Don't think so.
I'm not sure , but I think that the reset button is directly connected
to the reset pin of most chips and can not be overrided.
Off course this is the first candidate for a "reboot properly" button,
but there is no hardware support. That is why I used the power button,
which is ( more or less ) under software control.


>         Gerhard
> 
> On Fri, 23 Mar 2001, David Balazic wrote:
> 
> > I had a similar experience:
> > X crashed , hosing the console , so I could not initiate
> > a proper shutdown.
> >
> > Here I must note that the response you got on linux-kernel is
> > shameful.
> >
> > What I did was to write a kernel/apmd patch , that performed a
> > proper shutdown when I press the power button ( which luckily
> > works as long as the kernel works ).
> >
> > Ask me for details, if interested.
> > The patch was for 2.2.x IIRC, so I would have to rewrite it almost
> > from scratch.
> >
> >
> > Otto Wyss (otto.wyss@bluewin.ch) wrote :
> >
> > > Lately I had an USB failure, leaving me without any access to my system
> > > since I only use an USB-keyboard/-mouse. All I could do in that
> > > situation was switching power off and on after a few minutes of
> > > inactivity. From the impression I got during the following startup, I
> > > assume Linux (2.4.2, EXT2-filesystem) is not very suited to any power
> > > failiure or manually switching it off. Not even if there wasn't any
> > > activity going on.
> > >
> > > Shouldn't a good system allways try to be on the save side? Shouldn't
> > > Linux try to be more fail save? There is currently much work done in
> > > getting high performance during high activity but it seems there is no
> > > work done at all in getting a save system during low/no activity. I
> > > think this is a major drawback and should be addressed as fast as
> > > possible. Bringing a system to save state should allway have a high priority.
> > >
> > > How could this be accomplished:
> > > 1. Flush any dirty cache pages as soon as possible. There may not be any
> > > dirty cache after a certain amount of idle time.
> > > 2. Keep open files in a state where it doesn't matter if they where
> > > improperly closed (if possible).
> > > 3. Swap may not contain anything which can't be discarded. Otherwise
> > > swap has to be treated as ordinary disk space.
> > >
> > > These actions are not filesystem dependant. It might be that certain
> > > filesystem cope better with power failiure than others but still it's
> > > much better not to have errors instead to fix them.
> > >
> > > Don't we tell children never go close to any abyss or doesn't have
> > > alpinist a saying "never go to the limits"? So why is this simple rule
> > > always broken with computers?
> > >
> > > O. Wyss
> >
> > --
> > David Balazic
> > --------------
> > "Be excellent to each other." - Bill & Ted
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> 
> --
> Gerhard Mack
> 
> gmack@innerfire.net
> 
> <>< As a computer I find your faith in technology amusing.


-- 
David Balazic
--------------
"Be excellent to each other." - Bill & Ted
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